Yes, but what kind of hierarchy would it be? Like this:

#1 Princess Celestia (Leaders)
#2 Princess Luna (Co-Leaders)
#3 Princess Cadence (Moderators)
#4 Princess Twilight (?)
(Discord could be something related to wars and chaos but I'm not sure what # he would be.)

The rest would have to be a members rank because if it was a hierarchy for the mane 6, people would argue over who's the best pony.